Hepatic Mycotic Aneurysms in TAVI-Associated Infective Endocarditis Caused by Streptococcus Gallolyticus: A Case Report

Background and Clinical Significance: Infective endocarditis following transcatheter aortic valve implantation (TAVI) is a severe complication that may be associated with prosthetic valve dysfunction, local infectious extension, and systemic embolization. Visceral mycotic aneurysms are uncommon, particularly those involving the hepatic arterial circulation. Case Presentation: We report the case of an 80-year-old woman who developed Streptococcus gallolyticus TAVI-associated prosthetic valve endocarditis (TAVI-PVE) four months after valve implantation. Despite prolonged antimicrobial therapy and subsequent negative blood cultures, the clinical course was complicated by persistent prosthetic and periprosthetic echocardiographic abnormalities, cerebral and splenic embolic events, and new-onset abdominal pain. Contrast-enhanced computed tomography revealed two hepatic arterial aneurysmal lesions with surrounding inflammatory changes, consistent with mycotic aneurysms. After initially declining surgery, the patient underwent redo surgical aortic valve replacement; cultures of the surgically excised specimens were negative. Abdominal pain resolved and inflammatory markers normalized following surgery and continued antimicrobial therapy. Follow-up contrast-enhanced CT demonstrated marked interval enlargement of the hepatic arterial aneurysmal lesion to 28 mm × 28 mm × 26 mm despite clinical improvement and normalization of inflammatory markers. Conclusions: This case highlights that microbiological, clinical, and biological improvement does not necessarily indicate resolution of local cardiac or extracardiac structural complications and emphasizes the importance of repeated imaging, guideline-based antimicrobial therapy, timely source control, and multidisciplinary vascular management in complicated TAVI-PVE.